Study of the genetic structure of chicken lines with different response to the Avian Influenza Virus (AIV)

The study of host response to the Avian Influenza Virus (AIV) may provide information which could be used to control the spread of Avian Influenza (AI) in poultry. The identification of genetic factors in the chicken affecting resistance to AI would facilitate selective breeding to develop resistant flocks. In a previous study, in which we carried out experimental infections of chickens from different commercial and experimental lines with an H7N1 HPAIV strain, we identified differences in the response to the virus, with variable mortality rates between lines. Chicken response to infection was not associated with the Mx polymorphism causing the S631N substitution. However, a statistically significant association between line and the response to AIV was identified. In the present study we have investigated the genetic structure of the chicken lines used to assess whether the variation in response to AIV is associated with the different centres of chicken domestication, in the Indian sub-continent and in South-East Asia. The mtDNA of the birds used in the challenge experiment has been analysed and the lines have been genotyped for the microsatellite markers used in the AVIANDIV project (http://w3.tzv.fal.de/aviandiv/). These data are being analysed to investigate the population structure and explore possible associations between genetic clusters and response to AI infection. The mtDNA analysis did not produce specific genetic clusters showing that most lines do not have a specific maternal origin. Microsatellite marker analysis and assessment of association with AI are still in progress.